Optical wavelength division multiplex communication systems which perform optical wavelength division multiplex communication have been known (see, for example, Japanese Laid-open Patent Publication No. 2007-158727 and Japanese Laid-open Patent Publication No. 2006-211385). One of optical wavelength division multiplex communication systems of this type includes a plurality of transmission devices forming a communication network. Furthermore, the optical wavelength division multiplex communication system is configured to set each of the plurality of different paths for the corresponding one of the plurality of different wavelengths.
In this case, each path is formed by connection of spans each of which is a zone between adjacent two transmission devices in a communication network, or a single span in the communication network. Furthermore, the optical wavelength division multiplex communication system is configured to transmit an optical signal of each wavelength via a path set for the wavelength. The optical wavelength division multiplex communication system determines whether an optical signal of a wavelength may be newly transmitted.
Incidentally, in the above-described optical wavelength division multiplex communication system, when a span is newly used in order to transmit an optical signal of a wavelength, a newly usable wavelength (that is, an empty resource) varies in a path formed by the span. Therefore, if a span is newly used after a path is determined, it is preferable to determine whether the determined path still has a usable wavelength.
Also, when a span is newly used, the empty resource might vary in all of paths formed by the newly used span. However, when the above-described determination is performed on all of the paths formed by the newly used span, a load of processing for performing the above-described determination becomes too large. Accordingly, in this case, for example, processing (for example, path switching, and the like) on the basis of a determination result might be excessively delayed.
It is therefore an object of the present disclosure to provide a determination device which may solve the above-described problem in which “there are cases where a load of processing becomes too large”.